Head interconnect circuit with alignment finger

ABSTRACT

A head interconnect circuit for connecting transducer elements of a data head to drive circuitry including an alignment finger on a lead tip for aligning leads relative to connectors or solder pads for electrically connecting heads to drive circuitry. A method for connecting a head interconnect circuit to a printed circuit supported on an head actuator including aligning an alignment finger on the lead tip with a printed surface of a drive circuit for soldering leads on the lead tip to solder pads or connectors on the drive circuit.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to ProvisionalApplication Serial No. 60/100,246 filed Sep. 14, 1998, and entitled“HEAD GIMBAL ASSEMBLY INTERCONNECT ALIGNMENT”.

FIELD OF THE INVENTION

[0002] The present invention relates to a data storage device. Inparticular, the present invention relates to a head interconnect circuitfor electrically connecting transducer elements of a data storage deviceto process circuitry for read or write operations.

BACKGROUND OF THE INVENTION

[0003] Disc drive systems are well known which include data headsincluding transducer elements for reading or writing data to arecordable disc. Transdurer elements of the data heads are electricallyconnected to drive circuitry through a head interconnect circuit.Conductive paths on the head interconnect circuit electrically connecthead leads connected to transducer elements on the head to circuit leadsconnected to drive circuitry.

[0004] Heads are supported relative to a disc surface by a head actuatoror E-block. A drive circuit is mounted on the head actuator and circuitleads on the head interconnect circuit are connected to lead connectorsor solder pads on the drive circuit. Leads are supported along an edgeof a lead tip of the head interconnect circuit and connectors or solderpads are aligned along a slot or edge of the drive circuit. The lead tipis inserted into the slot or aligned with the edge to connect circuitleads to connectors. Leads are soldered to connectors to electricallyconnect transducer elements of the head to drive circuitry.

[0005] Prior to soldering, leads are aligned with the connectors orsolder pads to assure desired electrical connection for read and writeoperations. Drive circuits mounted on a head actuator or E-block includea conductive metal substrate supporting a printed circuit. Duringsoldering operation, solder can spill from the solder pad or connector.Solder spill to a conductive metal substrate can short the electricalconnection between the data heads and drive circuitry so that the dataheads are defective. The present invention addresses these and otherproblems, and offers other advantages over the prior art.

SUMMARY OF THE INVENTION

[0006] A head interconnect circuit for connecting transducer elements ofa data head to drive circuitry including an alignment finger foraligning leads relative to lead connectors or solder pads forelectrically connecting heads to drive circuitry.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a perspective illustration of a disc drive.

[0008]FIG. 2 is a perspective illustration of an actuator blocksupporting heads for read or write operations.

[0009]FIG. 3 is a perspective illustration of a head interconnectcircuit.

[0010]FIG. 4 is a detailed perspective illustration of a lead tip of ahead interconnect circuit and solder pads on a drive circuit.

[0011]FIG. 5 is a cross-sectional view of leads from multiple headinterconnect circuits soldered to solder pads of a drive circuit asgenerally taken along line 5,6-5,6 of FIG. 4.

[0012]FIG. 6 is an alternate cross-sectional view of leads from multiplehead interconnect circuits soldered to solder pads of a drive circuit asgenerally taken along lines 5,6-5,6 of FIG. 4.

[0013]FIG. 7 is a perspective illustration of an embodiment of a leadtip of a head interconnect circuit of the present invention including analignment finger.

[0014]FIG. 8 is a schematic illustration of the alignment finger of FIG.7 having an alignment edge aligned with a printed surface of a drivecircuit.

[0015]FIG. 9 is a plan view of a lead tip of an embodiment of a headinterconnect circuit of the present invention connected to a testconnector board prior to assembly in a disc drive.

[0016]FIG. 10 is an operation flow chart for connection of leads todrive circuitry.

[0017] The drawings are for illustration and the features illustratedtherein are not necessarily drawn to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018]FIG. 1. illustrates a rotary disc drive 50 including a discchassis 52, discs 54 and a head actuator or E-block 56. Discs 54 arerotationally coupled to chassis 52 via a disc spindle drive 58(illustrated diagrammatically) for rotation, as illustrated by arrow 59.Discs store data on concentric data tracks. The head actuator 56supports data heads 60 relative to a disc surface. In FIG. 1, headactuator 56 is rotated via operation of voice coil motor (VCM) 62 tomove heads 60 along an arcuate path as illustrated by arrow 64 toposition heads 60 relative to selected data tracks for read or writeoperations.

[0019]FIG. 2 is a perspective illustration of an embodiment of a headactuator 56 supporting heads 60. As shown in FIG. 2, head actuator 56includes a stem 66, a motor coil 68 and a pluality of stacked actuatorarms 70. A bearing 72 or other pivot connection rotationally connectactuator 56 to chassis 52. Bearing 72 extends through a bearing channel74 in the stem 66 to rotationally connect actuator 56 to rotationallysupport heads 60 for placement relative to selected data tracks. Motorcoil 68 is supported for operation in a backiron assembly 78(illustrated in FIG. 1) to form the VCM 62 for moving head actuator 56along path 64 for head placement relative to selected data tracks.

[0020] Flexible suspension assemblies 80 are coupled to and extend fromthe actuator arms 70 to support a plurality of heads 60 relative to thedisc surface. The suspension assemblies 80 illustrated in FIG. 2 includea load beam 82 and a gimbal spring 84. The load beam 82 and gimbalspring 84 flexibly support heads 60 relative to the disc surface tofollow the topography of the disc surface. Heads 60 include transducerelements for read or write operations. Transducer elements can beinductive type transducer elements, magneto-resistive and magnetoopticaltransducer elements. Transducer elements are electrically connected to adrive circuit 86 connected to head actuator 56 via a head interconnectcircuit 88.

[0021]FIG. 3 is a detailed illustration of an embodiment of a headinterconnect circuit 88. The embodiment shown includes base 90 having abody portion 92, and a tail 94; a plurality of head leads 96 and circuitleads 98. Head leads 96 are formed at an end of body portion 92 toelectrically connect to transducer elements supported on slider 100.Tail 94 extends from body portion 92 to a lead tip 104 supportingcircuit leads 98. A portion of the tail 94 extends along an actuator arm70 to position lead tip 104 proximate to the drive circuit 86(illustrated schematically in FIG. 3). Conductive paths 108 on base 90electrically connect head leads 96 to the circuit leads 98 forconnecting transducer elements to drive circuit 86 for read/writeoperations. Base 90 is typically formed of a flexible polyimide materialand the conductive paths 108 are formed of copper traces. The number ofleads 96, 98 and paths 108 depends upon the number of electricalconnections required for the transducer elements supported by the slider100.

[0022] As shown in FIG. 4, drive circuit 86 includes series of solderpads or connectors 110-1, 110-2, 110-3, 110-4 extending along a lengthof an interconnect slot 112 for connecting circuit leads 98-1, 98-2,98-3, 98-4 to drive circuitry. In the embodiment shown, upper and lowerlead pads 110-1, 110-2, 110-3, 110-4 are aligned along upper and lowerslot edges 112-1, 112-2 to connect circuit leads 98-1, 98-2, 98-3, 98-4for upper and lower head interconnect circuits 88-1, 88-2 as shown inFIG. 5 to electrically connect heads supported by upper and lowersuspension assemblies 80 connected to an actuator arm 70.

[0023] Circuit leads 98 extend along a lead edge 114 of lead tip 104 asshown in FIG. 4 and are spaced from end 116 to align each circuit lead98-1, 98-2, 98-3, 98-4 with a solder pad or connector 110-1, 110-2,110-3, 110-4. In the embodiment illustrated in FIGS. 4-5, lead tip 104is inserted into slot 112 so that an end 116 of the lead tip 104 abutsan end 118 of slot 112. Leads 98 are sequentially spaced along edgesurface 114 from end 116 to align with pads 110-1, 110-2, 110-3, 110-4when end 116 abuts end 118 of drive circuit 98. As shown, in FIGS. 4-5,leads 98 are bent and soldered to pads 110. Alternatively pads 110-1,110-2, 110-3, 110-4 can be spaced along an exposed edge surface (notshown) for connection of leads to drive circuitry.

[0024] As comparatively shown in FIGS. 5-6, the elevation of edge 114relative to a printed surface 120 (reference surface) of circuit 86affects placement of leads 98 relative to pads 110. As shown in FIG. 5,edge 114 is flush with printed surface 120 and in FIG. 6, edge 114 isout-of-alignment with or lower than printed surface 120. Alternatively,edge 114 can be raised relative to the printed surface 120. During thesoldering process, solder can spill from the solder pads 110 asillustrated diagrammatically in FIG. 6. The drive circuit 86 shown inFIGS. 5-6 is a rigid printed circuit board formed of a metal plate 122,such as Aluminum or stainless steel, and an insulating layer 124 such aspolyimide. Although a particular circuit board construction isdescribed, the circuit board is not limited to the specific constructionor materials described. Circuit paths 108 and solder pads 110 are formedon insulating layer 124. Depending upon the alignment of edge 114 withprinted surface 120 solder spill can interfere with and potentiallyshort the electrical connection between the head and drive circuitry.

[0025] In particular, as shown in FIG. 6, when edge 114 is lower thanprinted surface 120, solder spill 126 can contact the metal plate 122 ofthe circuit board shorting the head so that the head is defective. Thepresent invention relates to a head interconnect circuit 130 with analignment feature for aligning lead edge 114 relative to the printedsurface 120 or connector of drive circuit 86. An embodiment of the headinterconnect circuit 130 is illustrated in FIGS. 7-9 where like numbersare used to identify like parts of head interconnect circuit 88.

[0026] In the embodiment shown, the alignment feature includes analignment finger 132 on lead tip 134 having an alignment edge 136 foraligning lead edge 114 with printed surface 120 or connectors 110. Inthe embodiment shown, alignment edge 136 is co-planar with and alignedwith edge 114 on lead tip 134. As shown in FIGS. 7-8, the alignmentfinger 132 is inserted into the slot 112 to align the edge 136 with theprinted surface 120 or reference surface of the drive circuit 86.Alignment of edge 136 with reference surface aligns edge 114 withprinted surface 120 and solder pads 110 to reduce solder spill to metalplate 122. Alternatively, alignment edge of alignment finger 132 can belocated to align with a parallel back surface 138 to align edge 114 withprinted surface 120 or connectors 110. Engagement of the finger 132 withback surface 138 can secure the lead tip 134 in place and prevent thelead tip 134 from “popping out”.

[0027]FIG. 9 is a detailed illustration of lead tip 134. As shown, leadtip 134 is formed integral with a test connector board 140. Connectorboard 140 is used to test electrical connection of the heads prior toassembly in a disc drive. For assembly, connector board 140 is separatedfrom lead tip 134 as illustrated by line 142 and tab 144 is separatedfrom soldered leads 98. As shown separation of connector board 140 atline 142 forms finger 132. In the embodiment shown, lead tip 134includes a shoulder 146 and a shoulder flap 148. For assembly shoulderflap 148 is folded behind shoulder 146 and inserted into a slot (notshown) on actuator block 56 to secure lead tips for assembly to drivecircuit 86.

[0028]FIG. 10 is a flow chart for assembly. As shown for assembly, alead edge 114 is aligned with a connector edge 112-1, 112-2 of a printedor drive circuit as illustrated by block 150. Alignment finger 132 isused to align lead edge 114 with a printed surface 120 of the drivecircuit 86 as illustrated by block 152 and leads 98 are soldered toconnectors or solder pads 110 as illustrated by block 154.

[0029] A head interconnect circuit 130 for connecting transducerelements of a data head 60 to drive circuitry including a lead tip 104having a plurality of leads 98 aligned along a lead edge 114 and analignment finger 132 for aligning leads 98 relative to connectors orsolder pads 110 for connection to drive circuitry.

[0030] It is to be understood that even though numerous characteristicsand advantages of various embodiments of the present invention have beenset forth in the foregoing description, together with details of thestructure and function of various embodiments of the invention, thisdisclosure is illustrative only, and changes may be made in detail,especially in matters of structure and arrangement of parts within theprinciples of the present invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed. For example, the particular elements may vary depending onthe particular application while maintaining substantially the samefunctionality without departing from the scope and spirit of the presentinvention. In addition, although the preferred embodiment describedherein is directed to a magnetic disc drive system, it will beappreciated by those skilled in the art that the teachings of thepresent invention can be applied to other systems, like an optical datastorage system, without departing from the scope and spirit of thepresent invention.

What is claimed is:
 1. A head interconnect circuit for connectingtransducer elements of a data head to drive circuitry comprising: a baseincluding a tail having a lead tip; a plurality of head leads; aplurality of circuit leads along the lead tip; a plurality of conductivepaths electrically connecting the head leads and circuit leads; and analignment finger on the lead tip for aligning circuit leads relative toconnectors for electrically connecting heads to drive circuitry.
 2. Thehead interconnect circuit of claim 1 wherein circuit leads extend alonga lead edge of the lead tip and the alignment finger includes analignment edge for aligning the lead edge relative to a referencesurface of a circuit.
 3. The head interconnect circuit of claim 1wherein the circuit leads are longitudinally spaced along a lead edge ofthe lead tip and the alignment finger extends from an end surface of thelead tip.
 4. The head interconnect circuit of claim 3 wherein thealignment finger includes an alignment edge aligned with the lead edgefor aligning the lead edge relative to a printed surface of a printedcircuit.
 5. The head interconnect circuit of claim 4 wherein the leadtip is sized for insertion into a slot of the printed circuit havingsolder pads aligned therealong.
 6. The head interconnect circuit ofclaim 4 wherein the circuit leads are spaced from an end of the lead tipalong the lead edge to align with solder pads spaced along an edge ofthe printed circuit.
 7. The head interconnect circuit of claim 6 whereinthe alignment finger extends from an end of the lead tip and thealignment edge is aligned with the lead edge so that when the end of thelead tip abuts an end surface of the printed circuit and alignment edgeabuts a printed surface of the printed circuit, lead edge is relativelyflush with the printed surface of the printed circuit.
 8. The headinterconnect circuit of claim 1 wherein the base is formed of a flexiblematerial.
 9. The head interconnect circuit of claim 1 wherein the baseis formed of a polyimide material.
 10. The head interconnect circuit ofclaim 1 wherein the conductive paths are formed of copper traces. 11.The head interconnect circuit of claim 1 wherein the body is sized to bemounted on a flexible suspension assembly of a head actuator.
 12. A headinterconnect circuit for connecting transducer elements of a data headto drive circuitry comprising: a base including a tail having lead tiphaving a plurality of leads for connecting transducer elements to drivecircuitry; means for aligning leads for connecting leads to drivecircuitry.
 13. The head interconnect circuit of claim 12 wherein theleads are connected to connectors on a circuit and the means foraligning leads aligns leads relative to connectors to limit solder flowto a conductive substrate of the circuit.
 14. The head interconnectcircuit of claim 12 wherein leads extend along a lead edge of the leadtip and the means for aligning leads aligns leads along a lead edge withconnectors on a surface of a circuit.
 15. The head interconnect circuitof claim 12 wherein leads extend along a lead edge of the lead tip andthe means for aligning includes a finger including an alignment edge forpositioning the lead edge surface relative to a printed surface of aprinted circuit.
 16. The head interconnect circuit of claim 12 whereinthe means for aligning includes an end surface on the lead tip foraligning leads spaced along a lead edge with connectors spaced along anedge of a printed circuit.
 17. A method for connecting a headinterconnect circuit to a printed circuit supported on an head actuatorcomprising steps of: a) positioning a lead tip of a head interconnectcircuit having a plurality of leads aligned along an edge of the leadtip with an edge of a circuit having a plurality of connectors spacedtherealong; b) aligning an alignment finger on the lead tip with areference surface of the circuit to align lead edge relative toconnectors on the circuit; and c) soldering leads on the lead tip toconnectors on the circuit.
 18. The method of claim 17 further comprisingthe step of: d) aligniig an end of the lead tip with an end surface ofthe circuit for aligning leads with connectors on the circuit.
 19. Themethod of claim 17 wherein the reference surface is a printed surface ofthe circuit.
 20. The method of claim 17 wherein the reference surface isa back surface of the circuit.